Ships have been traveling the world for hundreds of years, why is there a problem now?
A. It is true that exotic species have successfully invaded foreign waters over the years. However, with the advent of “free trade,” the advanced speed of modern ships, and the enlarged volume of ballast water, the number of successful invasions is rapidly increasing. In addition, prior to the early 1970’s ballast water was less of a concern because many of our harbors were so polluted that neither native species nor alien species could survive in them. Q. What is “Open-Sea Exchange?” A. Ballast water exchange involves replacing coastal water with open-ocean water during a voyage. This process reduces the density of coastal organisms in ballast tanks that may be able to invade a recipient port, replacing them with oceanic organisms with a lower probability of survival in near-shore waters.
